French carmaker Renault has filed an official complaint against persons unknown for industrial espionage, saying it was the victim of corruption, theft and concealment in a case that has led French politicians to speak of "economic warfare".

REUTERS - French carmaker Renault kicked off a judicial investigation into industrial espionage on Thursday, alleging corruption, theft and concealment.

Renault did not name the perpetrators but said it had filed an official complaint following the discovery of serious misconduct detrimental to the company's "strategic, technological and intellectual assets."

Last week Renault suspended three executives on suspicion they had leaked information about its high-profile electric car technology in a case France has dubbed "economic warfare". This has prompted talk of tighter laws to protect its companies.

Renault Chief Operating Officer Patrick Pelata said the carmaker had been the victim of an organised international network but that key technology for electric vehicles, in which it is investing heavily, was safe.

The scandal threatened to harm improving relations between France and China, after a government source last week said intelligence services were looking into a possible China link.

The French government has since played down the possibility of a link to China, saying it is not accusing any one country of involvement, while China has denied any link to the case.